add missing parentheses

Author: javanna

docs/reference/modules/cross-cluster-search.asciidoc

@@ -14,7 +14,7 @@ When a remote cluster is registered, its cluster state is retrieved from one of
 _gateway nodes_ are selected to be connected to as part of upcoming cross cluster search requests.
 Cross cluster search requests consist of uni-directional connections from the coordinating node to the previously
 selected remote nodes only. It is possible to tag which nodes should be selected through
-node attributes (see <<cross-cluster-search-settings>>.
+node attributes (see <<cross-cluster-search-settings>>).
 
 Each node in a cluster that has remote clusters configured connects to one or more _gateway nodes_ and uses
 them to federate search requests to the remote cluster.